Electroplating apparatus.



" No. 838,716. v PATENTED DEC. 18', 1906. I

W. s. HUTGHINSO'N. BLEGTROPLATING APPARATUS.

APPLICATION FILED JULY 29.1906.

WILLIAM SPENCER HUTUHINSON, OF BOSTON, MASSACHUSETTS.

ELEOTROPLATI NG APPARATUS.

Specification of Letters Patent. I

Patented Dec. 18,1906.

Application filed July 29,1905. Serial to. 271,812.

To all whom it may concern:

Be it known that I, WVILLIAM SPENCER HUToHINsoN, a citizen of the UnitedStates, and a resident of Boston, in the county of Suffolk and State ofMassachusetts, have invented new and useful Improvements inElectroplating Apparatus, of which the following is a specification.

My invention relates to electroplating apparatus, and it consists of anovel combination of instrumentalities for recovering the valuablemetallic constituents used in electroplating solutions. In gold-plating,for instance, the articles to be coated carry with them adherent totheir surfaces a consider able quantity of the plating solution, and asit is essential that this plating solution be thoroughly rinsed from theplated article it is and has been the practice to immerse the platedarticles in an abundant stream of water, which removes from them theadherent solution. This practice involves two elements of waste. First,the solution itself is carried away in such a dilute condition that itis practically impossible to recover from it the matter in solution,and, second, the establishment where the plating is carried on uses adisproportionately large quantity of water for washing purposes andusually has to pay for this waste according to the showing of awater-meter.

In the drawings hereto annexed, which show an apparatus embodying myinventions and improvements, Figure 1 is a vertical longitudinal sectionon the line 1 1, Fig. 2, of the solution-recovering device; and Fig. 2,an end view of a typical plating equipment with my recovering apparatusincorporated therein.

A represents the plating vessels or tanks, wherein the metal articlesare immersed in order to be electroplated, say, with a superficial filmof gold. The gold solution-say cyanid-adheres to the plated articleswhen the plating is completed, and they are lifted from the platingtanks A. The platingtanks A are arranged in two rows, and between them Ierect the rinsing-tank B. This rinsing-tank is divided by partitions 6into compartments of suitable number, as B B B B. Each partition I)terminates at a level slightly below the top of the rinsingtank B, sothat water may flow progressively from' one compartment to another andfinally from the last compartment through a spout E, which communicateswith the first of a series of Zinc boXes C. I/Vater is sup plied to therinsing-tank B from a suitable spigot D. As the plated articles are readirection which is the reverse of that of the flow of rinsing-water fromspigot D to outlet.

E. The water in the compartment B in the normal progress of rinsingsuccessive lots of plated articles contains a moreconcentrated solutionof the plating liquid than the com partment B and the same progressiverelation persists through the successive com partment 13. Furthermore,as the plated articles are shifted from one compartment of therinsing-tank to the other in the direction named they carry a smallerand smaller proportion of valuable solution. The relation betweenquantity of solution carried by the plated article and the strength ofthe rinsing iquid is thus practically maintained. It has been foundinpractice that plated articles may be verythoroughly rinsed by thisprogressive method with the employment of a very small quantity of waterin circulation, and the final washing in a stream of water may be eitherwholly dispensed with or greatly reduced as to time and water quantity.In the instance used for illustration, where gold cyanid solution isrinsed from the plated articles, the recovering-boxes C are filled withzinc shavings or powered zinc, through which the rinse-water percolatesprogressively from boX to boX and finally from the last boX in theseries to the waste-pipe D. The zinc in these recovering-boxes isoccasionally removed and the valuablemetal deposited by reactiontherewith recovered.

In actual practice it has been demonstrated that a combined rinsing andrecovering apparatus such as above described will pay for its costseveral times over in a single year and that, moreover, the rinsingoperation is much easier to carry on than it is by the method heretoforeadhered to.

It may be found that under some conditions the liquid delivered from thefirst rinsing-compartment, as B may not be a sulficiently-concentratedsolution to be recovered by chemical deposit in the recoveringboxes inthe most advantageous manner. For instance, it has been found that undersome conditions the zinc in the recoveringboxes C has deposited upon ita film of gold plate, which is not the form best suited to finalrecovery. As a precautionary measure, therefore, and one which Irecommend to be used in all instances, I provide an enrichenriches therinse-water solution so that the chemical reaction in therecovering-boxes results in the disintegration of the Zinc and theformation of a slime or mud, from which the gold can very readily beextracted.

What I claim, and desire to secure by Let- 'ters Patent, is

1. In an apparatus of the character described, the combination of arinsing-tank subdivided into a series of compartments, an inlet forrinsing fluid at one end of the series,

an outlet, an enriching vessel communicating with the outlet end of theseries of rinsing-tank compartments comprising means for enriching therinse solution, and a recoving apparatus communicating with the outletfrom the rinsing-tank.

2. In an apparatus for the recovery of gold from plating solutions, thecombination of the rinsing-tank subdivided into a series ofcompartments, an inlet for rinsing fluid at one end of the series, anenriching vessel atthe other end of the series, and means therein forsupplying fresh cyanid to the rinse solution, an outlet from the saidenriching vessel and a series of zinc boxes communicating with the saidoutlet.

Signed by me at Boston, Massachusetts, this 25th day of July, 1905.

WILLIAM SPENCER HUTCHINSON.

Witnesses:

JosEPH T. BRENNAN GRACE E. GrBBoNs.

